Door-spring



JOHN MAXsoN, oii` DE RUYTER, NEW YORK. l,

DOOR-SPRING.

Specicaton of Letters Patent No. 5,784, dated September 19, 1848.

To all 'whom t may concern Be it known that I, JOHN MAXsoN, lof De Ruyter, in the county ofMadison and State of New York, have invented new and useful Improvements in Springs for Closing Doors, Gates, and for other Like or Similar Purposes, and that the following is a full, clear, and exact description of the principle or characterl which distinguishes them from all other things before known and of the manner of making, constructing, and using the same, reference being had to the accompanying drawings, making part of this specification, in which- Figure 1 is an elevation of a portion of a door with my improvements applied, and Fig. 2, a horizontal section thereof taken at the line (X, X) of Fig. 1, and looking in the direction of the, arrow.

The same letters indicate like parts in all the figures.

The object long since sought to be attained in door springs has been an `increase of power as the door closes, and as the tension of the spring necessarily decreases; but so far I am not' aware that any one has attained the desired object with that simplicity of construction that will insure cheapness, and

that absence from the liabilities to derangement which will adapt them to general d0- mestic use. f

The nature of my invention by which I` attain this desired end consists in combining with a helical spring provided with a roller or wrist, and connected with the door, a cam 1 is secured by screws a' metal tube or casev (d) in which is placed a helical spring (e) one end of which bears against the end of the case, and the other against the end of a small tube (f) that passes out through the other end of the case; a rod of metal (g) passes through a hole in the end (71,) of the case which answers the purpose of a guide,

thence through the whole length of the helical spring and then through the tube (f), and provided with a nut .(71) at the end by means of which the helical spring caw be contracted at pleasure to increase its tension on the door. The forward end ofthe rod (g) is provided with a roller that turns on a movable pin (la) so that it can be taken off at pleasurewhen it is desired not to use thespring, and replaced at any time. Y The periphery of this roller acts on the inner face of a cam formed rod (l) attached to the j amb of the door by screws or otherwise, and it will be seen by reference to Fig. 2, where the red line is a circle, ff

whosel center is the axis of the door hinge, that the form of the cam is suchthat it gradually runs out of the circle that the ten-v I sion of the spring may cause the roller to act on this cam in manner substantially similar to the descent of a weight on an inclined plane, and that'the more the line of the cam deviates from the line of the circle the. greater will be the inclination of the ,i

p lane, thus decreasing the amount of tension required in the spring to produce a given or desired effect. In this way as the door closes, the spring which gradually decreasesin tension, and if desired in a greater ratio, increases the effective force of its action on the door by reason of the change'in .the curve of the cam. 1

f At-thelpoint and from thence to the extremity I makek theicain straight, that is, a tangent to the curve that ends at the point (2'), that the spring may be suddenly increased inits eiective action on the door at force is increased as the tension of the spring decreases, substantially as described.

f 2. I also claim the method ofregulating the tension of the spring by combining therewith the screw rod that carries the 1l() roller that acts on the cam, the slidingtube, and the regulating nut, substantially as def scribed.

JOHN MAXSON, Witnesses:

ALEX PORTER BRowNE, J. J. GREENOUGH.

sov

Itached firmly to the door frame substantially `as herein described, whereby the edective 

